GB-A-2133831 (Societe Anonyme Goiot SA) discloses panel hinges which have a balancing coil spring coaxial with the axis of rotation. The spring substantially counter-balances the torque of the panel weight and so assists lifting of the panel. The hinges also include washers which form a friction brake between an element rigidly connected to the panel and an element rigidly connected to a deck. The frictional interaction and the braking torque thus provided are adjustable and enable the panel to remain at any angle between horizontal and vertical. The hinge system is situated along one outside edge of the panel and is therefore exposed to the weather and vulnerable to damage.
Tension springs are seen in GB-A-537185, acting between lever arms pivoted to each other and to a wall and to a door respectively. The pivot axis of the door is vertical. Abutments on the levers act on the springs at angles of opening of the door beyond 90.degree. so that it maintains the position to which it is put. At angles below 90.degree. of opening the springs urge the door closed.